Field of the Invention
The present invention relates to an information processing device, a traveling direction estimation method and a storage medium.
Related Art
Conventionally, in order to autonomously estimate the current position of a user, technology has been known for estimating the traveling azimuth of a user based on the output of an acceleration sensor provided in a device carried by a user that is walking (e.g., Japanese Unexamined Patent Application, Publication No. 2012-242179).
According to this system, the traveling azimuth of the user is calculated based on the direction of acceleration detected by the acceleration sensor and the azimuth detected by a geomagnetic sensor. The direction of acceleration used herein is a forward direction or backward direction relative to the orientation of the body of the user, i.e. basically the direction of the horizontal component of acceleration.
However, the direction of acceleration cannot be determined from only this horizontal component of acceleration.
This is because, every time the user takes a step forward by walking, only the horizontal component of acceleration, which changes alternately between the position direction and negative direction, is detected from an acceleration sensor, and further, for this horizontal component, the form of output differs according to in which direction this device is facing and carried by the user relative to the orientation of the body. For example, with a case of carrying so that the forward direction of the body of the user and the positive direction of the horizontal component of acceleration match, and a case of carrying so as to conversely match with the negative direction of the horizontal component, the horizontal component of acceleration detected will have the opposite positive/negative directions.
In this way, it is not possible to determine from only this horizontal component of acceleration whether the user is advancing forwards relative to the orientation of the body or advancing backwards.
Therefore, in Japanese Unexamined Patent Application, Publication No. 2012-242179, a method is being used that detects not only the horizontal component of acceleration, but also the vertical component, and detects in either of forwards or backwards of the user is advancing, based on the relationship of timings at which both of these components become peaks in the positive direction or negative direction.
However, it is known that, when the walking speed becomes high, i.e. when the user becomes running state, the relationship of timings at which the horizontal component and vertical component of acceleration each reach peaks will change.
However, the technology described in Japanese Unexamined Patent Application, Publication No. 2012-242179 persistently estimates the traveling direction on the premise that the user is walking.
For this reason, when the user becomes running state, the possibility for error arising in the estimation of traveling direction is high.
In other words, in the conventional technology, a situation has been brought about in which it becomes difficult to estimate the traveling direction of the forwards direction or backwards direction accurately, depending on the movement situation of the user, and accurate calculation of the traveling azimuth of the user and thus the current position thereby becomes difficult.